A car bomb explosion outside a major Shi'ite Muslim shrine and mosque in Najaf has killed one of Iraq's most important Shi'ite leaders and at least 75 other people.

The bomb exploded as Ayatollah Mohammed Baqer al-Hakim and worshippers were leaving the Imam Ali mosque after Friday prayers.

Relatives of Ayatollah Hakim and officials from the Supreme Council for the Islamic Revolution in Iraq, which he headed, confirmed the cleric died in the explosion.

The bomb exploded outside the shrine and near a row of shops in the Shi'ite Muslim holy city of Najaf, 180 kilometers south of the Iraqi capital, Baghdad.

On Sunday, a bomb killed three aides to another member of the Hakim family in Najaf. After that blast, Shi'ite officials said the attack could have been the work of Saddam Hussein loyalists, or the result of a feud between Shi'ite factions.

In an earlier incident north of Baghdad, U.S. military officials say one American soldier was killed when insurgents fired rocket-propelled grenades at a convoy on a main road in As Suaydat, near the flashpoint town of Baquba. Three other soldiers were wounded.

Meanwhile, the top U.S. commander for Iraq says he would like to see peacekeepers from more Muslim countries join American troops already in Iraq.

In an interview with The New York Times newspaper published Friday, Army General John Abizaid rejected calls by some U.S. lawmakers to increase the number of U.S. troops in Iraq. Instead, he said the size of Iraq's own revamped security services should be increased.

The head of the U.S. Central Command also said other nations, particularly Muslim countries such as Pakistan and Turkey, should be persuaded to contribute peacekeeping troops in Iraq.